In a new escalation of hostility between Washington and Pyongyang, North Korea's foreign minister warned in a United Nations speech Saturday that a rocket attack on the U.S. mainland was "inevitable," while U.S. warplanes flew off the east coast of North Korea in an explicit show of force.

The eight U.S. aircraft remained in international airspace and flew the farthest north of the demilitarized zone between North Korea and South Korea that American warplanes have flown since Pyongyang started testing ballistic missiles and nuclear weapons in the 1990s, the Pentagon said.

At the U.N. General Assembly, North Korean Foreign Minister Ri Yong Ho said U.S. President Donald Trump's recent comments about Kim Jong Un and North Korea would have consequences. "He committed an irreversible mistake of making our rockets' visit to the entire U.S. mainland inevitable all the more," Mr. Ri said.